临南洼陷营子街地区沙三下亚段油气富集主控因素

Main controlling factors in hydrocarbon accumulation of lower Sha 3 in Yingzijie area of Linnan Sag

营子街地区临近洼陷的生烃中心,但由于构造简单,缺乏构造圈闭,传统上认为勘探潜力不大。为突破勘探瓶颈,从沉积演化、相带类型研究出发,在优势砂体类型、烃源岩压力及隐蔽圈闭的综合分析基础上,对营子街地区沙三下亚段油气成藏富集因素进行了研究。结果表明,营子街地区沙三下亚段沉积时期发育席状砂和浊积扇两类优势砂体,并夹持包裹于烃源岩中,形成了隐蔽型岩性油藏,其成藏富集因素主要受烃源岩超压和有效储层2个因素的控制,其中烃源岩超压控制了油气充满度,烃源岩超压区范围内有效储层的分布控制了含油规模,由此建立了自生自储-超压控藏型成藏模式。

Although Yingzijie area is near the hydrocarbon generation center, because of its simple structure and the lack of structural traps, traditionally, the exploration potential is considered not great. In order to overcome the exploration obstacles, the sedimentary evolution and the facies types are studied in this paper. Based on the dominant sand-body types, the hydrocarbon source rock pressure and the subtle traps, the main controlling factors in the hydrocarbon accumulation of lower Sha 3 in Yingzijie area are analyzed. It is shown that there are two kinds of dominant sand-bodies： The sheet sand and the turbidite fan sand. These sand-bodies are surrounded by the source rock with the reservoir types being subtle lithologic, where the hydrocarbon accumulation factors are controlled by the overpressure of the source rock and the effective reservoirs. The oil fullness degree of the reservoirs are controlled by the overpressure of the source rock and the.oil scale is controlled by the effective reservoirs in the region of the overpressure of the source rock, and the accumulation model can thus be built, as the self-source and the self-reservoir and the overpressure controlling accumulation.